Skiving machine



Dec. 13, 1955 J. R. HAWKINS 2,725,489

SKIVING MACHINE Filed May 31, 1951 3 Sheets-Sheet l IN V EN TOR.

AT T ORNE Y Dec. 13, 1955 HAWKINS 2,726,489

SKIVING MACHINE 3 Sheets-Sheet 3 Filed May 31, 1951 IN VEN TOR.

ATTORNEY.

United States PatentOfiiice 2,726,489 Patented Dec. 13, 1955 This invention relates'to a-skivin'gmachine. The machine is particularly usefulin skivingor abrading aforward edge of an abrasive-eoated belt for the joining of the belt edges. The machine, however, is useful tor various other skivin'g operations.

-In the forming of an abrasive belt, it'is commonto "take a long strip of'abrasivepaper and'after cutting the ends of the strip along diagonal lines, tounitethe'ends, at least one of the ends being skived along its edge to remove the abrasive therefrom and preferably a portion of the paper. It is important that thejoi'ned end of the beltbe'ofsubstantially the same thickness as the remain- 'ing portions of the belt, and for this reason the abrasive is completelyremoved along one edge and portions of the paper are usually removed from the edge portions where the'junctionis made. 'When 'the parts are finally secured and compressed, a' joint is obtained whichjis' of substantially the same thickness as the other portions of the 'belt. 1

In 'the'above operation, it will be recognized that extreme 'accuracyris required. The edge which 'is to .be 'skiv'ed orabraded must be accurately aligned with the abrading wheel, etc. and means must be provided .-f0r gripping the end portions adjacent the edge whichis to be skived. Accurate placing' of. the edge portion ofthepaper represents a serious problem whichhas not heretofore been solved. Thep'robl'em is further complicatedby the fact that the abrasive wheel, after passing over the abrasive-equipped top surface, is renderedirregularin itself due to the contact with the abrasive .grains, and such an irregular surface would subsequently have to be applied'to the delicatepaper areas. Furthensincethe cuts which are to be made into the paper or" backing portion' must be or extreme accuracy to prevent-the destruction of the paper backing, etc., means forsupport which willpermit such fine adjustment of thecuttingOr ab'ra'd ing means are demanded.

Anlobject' of the present invention is to providemechani'sm satisfying the above needs-and permitting accurate cutting of the paper or backing portions to adesired depth without injuring the backing structure and while at the same time removingthe abrasive'from' one' edge portion thereof. A still further'object is 'to'provide in such a structure means whichwill align the' 'fo'rwa'rd edge portionvofthesheet to permit engagement of the sheet at a point rearwardly-of 'the'edge'portion while at the same' time providing for the retracting of the aligning means tolpermit the movement'of an abrasive wheel over the exposed edge of the sheet.

A still further object is to' provide in such a structure means for raising and lowering the abrasive wheel and for advancing it while rotating over-the exposed edge of the sheet. Yet another object-is toprovidemeansfor dressing the edge of thewheelby the use of'adiamond point after the wheel has become irregularas'amesult of' its passage over the abrasive surface and-to thus press against the paper or backing portion of the sheet a true abrasive wheel edge. h

A still'fur'ther object is to provide in such an apparatus means for accurately aligning the edge portion of a sheet upon the bed and for clamping the same while in such position and then subsequently removing the aligning means to permit the movement of a carriage carrying a rotating abrasive wheel across the exposed edge ofthe sheet. Yet another object is to provide in such a structure means for raising andlowering the wheel and carrying'away the abrasive and abraded particles, etc. while at'the same time providing carriage means for moving the wheel and other structure back and forth across the bed of the machine and along the exposed edge portion of 'thesheet. Other specificobjects and advantages will appear as the specification proceeds.

The invention is shown in an illustrative embodiment by thetaccompanying drawings, in which p v Figure 1 is a top plan view .of apparatus embodying my invention; Fig. 2, .a perspective view of a belt formed by the uniting of edges of an abrasive strip treated in the apparatus shown; Fig. 3, a side view in elevation of the machine shown inFig. 1; Fig. 4, a brokenenlarged detail view showing the abrasive wheel engaging an exposed edge portion of the sheet and with the tsto'p fingers in lowered position; Fig. 5, a view similar to Fig. 4 but showing the presser device elevated and the stop finger means in elevated position for aligning'the forward edge portions of the sheet; Fig. 6, an enlarged broken detail view showing the diamond dresser or point arranged for movement across the edge of the rotating abrasive wheel; and Fig. 7, an end portion of the machine.

In the illustration given, A designates a casing providing a bed 10. The bedlti is adapted to receive asheet 11 which is to have a forward edge portion thereof abraded andthe sheet may be provided on one side with abrasive, etc.

Over the bed 10 is supported a bridge 12 having standards 13 spacing the upper portion of the bridge 12 above the bed 10. The sheet 11 is normally passed under the bridge 12 and toward the forward end of the machine.

Carried by the bridge 12 are a plurality of presser devices 14. In the illustration given, thepre'sser. devices comprise cylinders having mounted therein pistons '15 'and'piston stems 16. The lower ends of the pistonsterns I 'G-areequipped with pressure shoes 17, and preferably the shoes "17 aresecured to a continuous presser platelg. The plate 1 81 may be pressed upwardly to provide reinforcingribs i9 extending'between' the shoe portionsgl7, asshown'more clearly in Fig. 3. It willbe unders'tood that any suitable presser plate means may be employed. The pressure fluid, which may be compressed van, or

which may consist or a liquid such as oil under. pressure,

is supplied to the upper ends of the cylinders 141w the conduits 20, which'in turnare connected to the manifold '21 leading toasu itable sourceof fluid pressure. v

Spaced-forwardly of the presser plate 18 area, plurality of step-or alignment fingers 22; In the illustration-given, the fingers 22 are secured to an angle iron bar .23, the ends of which are preferablyguided for vertical movement in the slotted blocks 24; the slots being shown at 24d.- 7 The bar'23 is' in turn mounted upon therplun'ge'rs of a-n'urrib'e'r of pistons 26 of fluid pressure cylinders 27, and" compressed air or other fluid under pressureis' suppliedto the lower portions of the cylinders 27 below the pistonsthereof through the conduits 28. Thus when the pressure fluid is supplied to the lower portions of the cylinders 27, the pistons 26 are raised against the force'of springs 28a to elevate the ba'r 23 and thus the spaced stop fingers 22' move to the position shown in" Fig. 5. In the raised position thus shown, the (fingers: engage the forward edge portion of the abrasive sheetlI and cause its forward edge portion to be accurately aligned. After the sheet 11 has thus been accurately placed upon the bed 10, the pressure fluid is applied to the upper cylinders 14 and the pressure shoes 17 and plate 18 are brought downwardly upon the sheet 11. Simultaneously with the application of the presser device to the top portion of sheet 11, or immediately thereafter, the pressure fluid is released from the cylinders 27 and the fingers 22 drop below the top surface of the bed 10. Several different structural arrangements may be readily used to permit movement of the fingers 22 into extended position above the bed 19 and into retracted position clear of the bed. The important concept is that the fingers 22 must operate as stops or aligning means for a sheet upon the bed and must be retracted clear of the sheet during the abrading operation.

After the fingers 22 have retracted, the way is clear for the movement of an abrasive wheel and the supporting means therefor over the exposed edge portion 11a of the sheet.

In the illustration given, B designates a carriage device equipped with rollers 29 for movement along the bed 10. Preferably the bed 10 is provided with a stepped-down portion 10a to provide a track for the carriage B, as shown more clearly in Fig. 7. By providing the steppeddown portion 10a of bed 10, there is provided a vertical wall 10b between the two portions of the bed 10 and the fingers 22 may be conveniently supported along the edge of the upper bed portion 10, as shown more clearly in Figs. 4 and 5. A continuous chain 30 is provided for drawing the carriage across the bed forwardly and backwardly. Upon the carriage is mounted a support 31 which is connected to the carriage by screw means operated by an adjusting handle 32. Thus by rotating the handle 32, the support 31 may be raised and lowered. Mounted in the support is a driveshaft 33 and on the rear end of the driveshaft is mounted an abrasive grinding wheel 34. A motor 35, which is also mounted upon the carriage, drives the shaft 33 through the drive belt and sheave structure 36 shown in Fig. 1. Thus the carriage B carries its own drive mechanism for the abrasive wheel shaft and the abrasive wheel shaft is adjustable in a vertical direction by turning the wheel 32 and thereby the thread means which support the shaft support 31 upon the carriage B.

The bridge structure 12 may be equipped with brackets 37 for supporting cables to movable contacts or switches 47a that limit the carriage travel and operate motor 47. That is to say, contact switches of conventional construction and which are in circuit with the motor 47 and are operative when actuated to reverse the motor are adjustably mounted upon the bridge structure. By adjusting the position of these switches the extent of travel of the abrasive wheel is determined and the apparatus may be adapted to accommodate sheets of various widths and abrading may start from either the right or left hand side of the bed.

In order to remove abrasive particles and other particles formed in the action of the abrasive wheel against the sheet, I prefer to equip the carriage B with a suction pipe 38 which is flexibly connected to an exhaust aperture or conduit.

After the abrasive wheel 34 has passed across the abrasive-equipped top surface of sheet 11, the exposed edge of the abrasive wheel is rendered irregular by such contact with the abrasive, and I prefer to true the edge of the abrasive wheel before it comes in contact with the paper or other supporting sheet where an extremely accurate removal of a small portion of the paper must be made. To accomplish this, I provide a diamond or dresser point 39 on a plate 40 and the plate 40 is guided for inward movement across the edge of the abrasive wheel 34. A link 41 is connected to the plate 40 and at its outer end is pivotally connected to the lever 42. The lever 42 is pivoted at 43 to the frame and the other end of the lever 42 is equipped with a handle 44.

Since the wheel 32, which elevates the support 31 for the abrasive wheel shaft 33 should be turned to give very fine adjustments with respect to the elevation of the abrasive wheel 34, I prefer to equip the support 31 with a micro-scale 45, as shown more clearly in Fig. 7.

The fluid for operating the finger-raising cylinders 27 and the presser plunger cylinders 14 may, if desired, be passed through electrically-controlled valves 46, whereby upon the release of pressure in cylinders 27 for the dropping of the fingers 22, pressure fluid is simultaneously directed into the cylinders 14 to bring about a downward movement of the presser plungers 16. It will be understood, however, that separate valves which may be handoperated or controlled by solenoids, may be employed for the separate or joint actuation of the pressure fluid devices.

A motor 47 may be provided in the lower portion of casing A, as shown in Fig. 3, and employed for operating the chain mechanism by which the carriage B is reciprocated across the stepped-down portion 10a of bed 10.

As is seen best in Fig. 1, the presser plate extends across the bed 10 with its forward edge spaced rearwardly of the edge of the bed but closely adjacent the wheel 34. The plate 18 is provided with a plurality of spaced-apart, rearwardly extending slots or recesses 48 therein aligned with the stop fingers 22.

Operation In the operation of the apparatus, pressure fluid is supplied to the stop finger cylinders 27 to bring about the raising of the fingers to the position shown in Fig. 5. At the same time, the pressure fluid is excluded from the presser cylinders 14 and the piston 15 of each plunger 16 is held in raised position through the action of the spring 14a. The operator presses the forward edge of the abrasive sheet or other sheet which is to be skived forwardly under the bridge 12. If the forward edge of the paper is inclined as in the illustration given in Fig. 6, the inclined edge which is to be treated is pressed against the stop fingers 22, as illustrated more clearly in Fig. 5. Thus the edge portion of the sheet at its forward end is brought into alignment and against the fingers 22. Pressure fluid is then diverted into the cylinders 14 and the presser plate 18 is brought downwardly against the sheet 11 at a point spaced rearwardly of the forward edge thereof. The fingers 22 are retracted by releasing pressure fluid from the cylinders 27 and the fingers 22 fall to the position shown in Fig. 4, thus clearing the way for action upon the exposed portion 11a of the sheet 11 by the abrasive wheel 34. The carriage B is then propelled across the bed 10a, bringing the rotating abrasive wheel 34 into contact with the exposed edge 11a of the sheet 11. Ordinarily, the carriage is started at the left-hand side of the machine as viewed in Figs. 1 and 3, and moved to the right. In this action, the abrasive wheel cuts away the abrasive on the exposed surface 11a of sheet 11. In so doing, however, the abrasive wheel is worn to an irregular condition by the time it reaches the right-hand side of the machine. At this point, the operator lowers the abrasive wheel to dress the abrasive wheel to the proper height from the bed of the table. As the diamond point traverses the edge of the rotating abrasive wheel 34 at a fixed elevation, the edge of the abrasive wheel is dressed and rendered again regular and true. It will be understood that in the dressing of the abrasive wheel 34, the wheel 32 is moved to a desired distance to bring the abrasive wheel 34 downwardly against the diamond point 39.

The diamond is set to the correct height so that after dressing, the abrasive wheel will be brought into the correct position for the remaining cut on the skive.

After an edge of the sand belt or abrasive belt has been treated as above described, adhesive may be applied to the exposed and treated edge to join the edges along a diagonal line, as illustrated in Fi g. 2.

After the treating of the edge as above described, the sheet 11 is released by relieving the cylinders 14 of the pressure fluid so that under the force of springs 14a, the pistons 15 are moved upwardly, as illustrated in Fig. 5. For treatment of another edge, the steps follow in the sequence above described.

The foregoing description illustrates the eifectiveness of the device for the treatment of abrasive-equipped sheets where it is desired to remove first the abrasive along one edge portion and thereafter a portion of the paper or other backing material. It will be understood, however, that the skiving mechanism shown may be utilized for the treatment of other materials and sheets.

While in the foregoing specification, I have set forth certain structure in considerable detail for the purpose of illustrating an embodiment of the invention, such details of structure maybe varied widely by those skilled in the art without departing from the spirit of my invention.

I claim:

1. In a skiving machine adapted for abrading the end portions of an abrasive belt, a relatively fiat bed, a plurality of aligned stop fingers arranged for movement between a retracted position and a position extending above said bed for engagement with the end of a belt to be abraded for aligning the same, means for moving said fingers to said position, presser means comprising a presser plate extending across said bed and spaced rearwardly from said stop fingers, means for moving said presser plate between positions above said bed and downwardly theretoward to engage a belt supported upon the bed and exert holding pressure thereagainst, and an abrasive wheel movable across said bed for engagement with the forward end of a belt supported thereon, said presser plate having a plurality of rearwardly extending recesses therein, each aligned with one of said stop fingers.

2. The structure of claim 1 in which said stop fingers are oriented for movement in a plane substantially normal to said bed.

3. In a skiving machine adapted for abrading the end portion of a relatively flexible sheet, a bed, retractable stop members extending transversely across said bed in spaced-apart, aligned relation and being adapted when raised to extend above said bed to engage the forward edge of a sheet supported thereon and when retracted to lie below the surface of said bed, means for selectively raising and retracting said stop fingers, a presser apparatus comprising an elongated presser plate extending transversely across said bed and being in substantially parallel alignment with said stop fingers, said plate being engageable'with a sheet supported upon said bed closely to and spaced rearwardly of said stop fingers, means for moving said presser plate into engagement with a sheet supported upon said bed and for withdrawing the presser plate therefrom, and a carriage movable transversely across said bed and being equipped with an abrasive wheel adapted to abrade the foreward edge of a sheet supported upon the bed, said presser plate having a plurality of spaced-apart slots extending rearwardly from the forward edge thereof,

6 each of said slots being aligned with one of said stop fingers.

4. The structure of claim 3 in which said stop fingers are mounted for movement in planes substantially normal to the surface of said bed and in which fluid pressure means are provided for actuating said stop fingers substantially simultaneously to raise the same above the surface of said bed.

5. In a skiving machine, a bed adapted to receive a sheet thereon, the forward end of which is to be skived, a plurality of fluid actuated presser members extending across said bed and being adapted to engage a sheet supported thereon for holding the same in position upon the bed, fluid pressure means for actuating said presser members, a plurality of stop fingers oriented in spaced-apart relation and in substantial alignment across said bed, said fingers being movable and arranged to move in planes substantially normal to the surface of said bed to an elevated position above the bed and to a retracted position below the surface of the bed, fluid pressure means for actuating said fingers, a carriage movable across said bed and being equipped with a rotatable abrasive wheel adapted to abrade the forward edge of a sheet held upon the bed by'said presser members, said stop fingers and said presser members being operatively associated so that when said presser members are moved into engagement with a sheet supported upon said bed, said stop fingers are returned to retracted position.

6. The structure of claim 5 in which valve means is provided in an operative arrangement with said presser members and said stop fingers for controlling the flow of pressure fluid to actuate the same in a relationship such that when said presser members engage a sheet upon said bed pressure fluid for actuating said stop fingers is released, biasing means for said stop fingers being provided for retracting the same.

7. The structure of claim 6 in which said presser members are equipped with a presser plate extending across said bed in parallel alignment with said stop fingers, said presser plate being provided with slots therein aligned respectively with said stop fingers.

References Cited in the file of this patent UNITED STATES PATENTS 508,196 Willson et al Nov. 7, 1893 937,912 Bailey Oct. 26, 1909 1,275,569 LaHodney et al. Aug. 13, 1918 1,881,185 Hazelton Oct. 4, 1932 2,390,967 Swenson et al. Dec. 11, 1945 2,416,121 Schreiber et al. Feb. 18, 1947 2,507,298 Brunner et al May 9, 1950 2,555,317 Chaplik June 5, 1951 2,579,337 Reaser et al. Dec. 18, 1951 2,597,180 Reaser et al. May 20, 1952 2,600,127 Reaser et al. June 10, 1952 

